SN74LS139ANG4

Overview

The SN74LS139ANG4 is a dual 2-line to 4-line decoder/demultiplexer from the Texas Instruments 74LS series. It operates on a single 5V supply with a voltage range of 4.75V to 5.25V. The device features Schottky clamping for high performance and includes two independent decoders within a 16-pin SOIC package. Each decoder utilizes two address inputs and an active-low enable input to select one of four active-low outputs. The component supports surface-mount installation and functions reliably within a commercial temperature range of 0°C to 70°C.

Feature Summary

• Dual independent 2-to-4 decoding channels
• Active-low output selection
• Schottky-clamped logic structure
• Single 5V power supply operation

Applications

• Address decoding in microprocessor systems
• Data demultiplexing applications
• Memory chip select generation
• Control signal routing

Procurement Notes

Verify the G4 suffix indicates lead-free and RoHS compliance status. Confirm the A suffix denotes the commercial temperature grade (0°C to 70°C). Ensure the package matches the 16-SOIC specification. Cross-reference the manufacturer part number against official Texas Instruments documentation to validate authenticity and specific revision details before procurement.

Selection Notes

Select this component when dual low-side decoding or demultiplexing is required in standard 5V logic environments. The LS family offers a balance of speed and power consumption suitable for general-purpose digital circuits. Verify that the active-low output polarity aligns with downstream input requirements. Consider the 16-pin SOIC footprint for PCB layout compatibility.

Part Context

This part belongs to the widely adopted 74LS (Low-power Schottky) logic family, known for improved switching speeds over standard TTL while maintaining lower power dissipation. The SN74LS139 variant specifically provides dual decoding capabilities, making it a staple in legacy and industrial digital design for managing multiple peripheral selections efficiently.

Replacement Considerations

SN74LS139ADR

FAQ

What is the logic function of the enable inputs?

The enable inputs are active-low. When an enable input is held high, all corresponding outputs remain in the inactive high state regardless of the address inputs.

How does the device handle unused outputs?

Unused outputs will remain in the high state when their respective decoder is disabled or when no valid address combination is selected for the enabled decoder.